首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18130篇
  免费   923篇
  国内免费   89篇
耳鼻咽喉   145篇
儿科学   294篇
妇产科学   201篇
基础医学   2279篇
口腔科学   448篇
临床医学   1184篇
内科学   4061篇
皮肤病学   1253篇
神经病学   1719篇
特种医学   681篇
外科学   2698篇
综合类   123篇
预防医学   584篇
眼科学   208篇
药学   1682篇
中国医学   51篇
肿瘤学   1531篇
  2023年   101篇
  2022年   186篇
  2021年   326篇
  2020年   181篇
  2019年   245篇
  2018年   347篇
  2017年   262篇
  2016年   329篇
  2015年   340篇
  2014年   459篇
  2013年   491篇
  2012年   832篇
  2011年   818篇
  2010年   516篇
  2009年   408篇
  2008年   776篇
  2007年   846篇
  2006年   842篇
  2005年   784篇
  2004年   815篇
  2003年   808篇
  2002年   763篇
  2001年   604篇
  2000年   675篇
  1999年   626篇
  1998年   262篇
  1997年   179篇
  1996年   170篇
  1995年   164篇
  1994年   126篇
  1993年   112篇
  1992年   444篇
  1991年   391篇
  1990年   408篇
  1989年   433篇
  1988年   400篇
  1987年   374篇
  1986年   324篇
  1985年   292篇
  1984年   171篇
  1983年   154篇
  1982年   89篇
  1979年   165篇
  1978年   81篇
  1977年   84篇
  1974年   73篇
  1973年   80篇
  1972年   84篇
  1970年   74篇
  1969年   70篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.

Purpose

Suppression of respiratory movement of the liver would be desirable for high-precision radiation therapy for liver tumors. We aimed to investigate the effect of our original device-free compressed shell fixation method and breathing instruction on suppression of respiratory movement. The characteristics of liver motion based on the movement of a fiducial marker were also analyzed.

Methods and Materials

First, respiratory amplitudes of the liver with the device-free compressed shell were analyzed from the data of 146 patients. The effect of this shell fixing method on liver movement was evaluated. Second, as another cohort study with 166 patients, interfractional internal motion of the liver for patients fixed in the shell was calculated using the fiducial marker coordinate data of images for position setting before daily irradiation. Third, in another 12 patients, intrafractional internal motion was calculated from the fiducial marker coordinate data using x-ray images before and after irradiation.

Results

The median respiratory movement without the shell, after fixing with the shell, and after instructing on the breathing method with the shell was 14.2 (interquartile range, 10.7-19.8), 11.5 (8.6-17.5), and 10.4 mm (7.3-15.8), respectively. Systematic and random errors of interfractional internal motion were all ≤2 mm in the left-right and anteroposterior directions and 3.7 and 3.0 mm, respectively, in the craniocaudal direction. Systematic and random errors of intrafractional internal motion were all ≤1.3 mm in the left-right and anteroposterior directions and 0.8 and 2.4 mm, respectively, in the craniocaudal direction.

Conclusions

The device-free compressed shell fixation method was effective in suppressing the respiratory movement of the liver. Irradiation position matching using the fiducial marker can correct the interfractional internal motion on each day, which would contribute to the reduction of the margin to be given around the target.  相似文献   
3.
4.
5.
6.
neurogenetics - Mediator (MED) is a key regulator of protein-coding gene expression, and mutations in MED subunits are associated with a broad spectrum of diseases. Because mutations in MED17...  相似文献   
7.
Abstract

This research explores how the level of consumers’ need for cognition (NFC) is associated with celebrity endorser credibility and examines its effects on advertising-related attitudes. A 3 (endorser types: actor/actress, athlete, TV personality/talent) × 2 (endorser’s gender) factorial experiment with 435 Japanese consumers was conducted. Concerning Japanese OTC drug advertising, lower NFC individuals perceived celebrity endorsers as more credible in comparison to higher NFC individuals. The main effects of NFC and endorser type on endorser credibility existed; however, no interaction between the two variables was found. The endorser type had an influence on attitudes toward ads and the advertised brand.  相似文献   
8.
9.
Mutations in the gene encoding 11beta-hydroxysteroid dehydrogenase type 2, HSD11B2, cause a rare monogenic juvenile hypertensive syndrome called apparent mineralocorticoid excess (AME). In AME, defective HSD11B2 enzyme activity results in overstimulation of the mineralocorticoid receptor (MR) by cortisol, causing sodium retention, hypokalemia, and salt-dependent hypertension. Here, we have studied whether genetic variations in HDS11B2 are implicated in essential hypertension in Japanese hypertensives and the general population. By sequencing the entire coding region and the promoter region of HDS11B2 in 953 Japanese hypertensives, we identified five missense mutations in 11 patients (L14F, n = 5; R74H, n = 1; R147H, n = 3; T156I, n = 1; R335H, n = 1) and one novel frameshift mutation (4884Gdel, n = 1) in a heterozygous state, in addition to 19 genetic variations. All genetic variations identified were rare, with minor allele frequencies less than 0.005. Four of 12 patients with the missense/frameshift mutations showed renal failure. Four missense mutations, L14F, R74H, R147H, and R335H, were successfully genotyped in the general population, with a sample size of 3,655 individuals (2,175 normotensives and 1,480 hypertensives). Mutations L14F, R74H, R147H, and R335H were identified in hypertensives (n = 6, 8, 3, and 0, respectively) and normotensives (n = 8, 12, 5, and 0, respectively) with a similar frequency, suggesting that these missense mutations may not strongly affect the etiology of essential hypertension. Since the allele frequency of all of the genetic variations identified in this study was rare, an association study was not conducted. Taken together, our results indicate that missense mutations in HSD11B2 do not substantially contribute to essential hypertension in Japanese.  相似文献   
10.
We report a 53-year-old woman with severe Graves' ophthalmopathy accompanied by uncontrolled myasthenia gravis. She presented remarkable exophthalmos, chemosis, and restriction of eye movement. Despite plasma exchange, steroid pulse therapy, local injection of steroid, and irradiation, ocular symptoms did not ameliorate. Since optic neuropathy was seen, orbital decompression surgery was performed in the left eye. Bilateral chemosis was improved after the surgery. Five years after surgery, there was no ocular palsy in the operated left eye, but in the contralateral eye. For the good prognosis of the eye movement, orbital decompression might be recommended in the severe Graves' ophthalmopathy accompanied by the optic neuropathy and/or ophthalmoplegia with proptosis.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号